User device dormancy

ABSTRACT

In a particular embodiment, a method includes sending a message from a communication device to a radio network controller. The message indicates that a data session has ended. The data session is supported by a wireless channel between the communication device and the radio network controller. After a time period following the sending of the message, a second message is selectively sent to the radio network controller. The second message indicates that the data session has ended. The second message is selectively sent based at least in part on whether a measurement indicates that data was communicated via the wireless channel during the time period.

I. CLAIM OF PRIORITY

The present application claims priority from U.S. Provisional PatentApplication No. 61/367,160 filed on Jul. 23, 2010, the contents of whichare expressly incorporated herein by reference in their entirety.

II. FIELD

The present disclosure is generally related to wireless communicationsystems.

III. DESCRIPTION OF RELATED ART

Advances in technology have resulted in smaller and more powerfulcomputing devices. For example, there currently exist a variety ofportable personal computing devices, including wireless computingdevices, such as portable wireless telephones, personal digitalassistants (PDAs), and paging devices that are small, lightweight, andeasily carried by users. More specifically, portable wirelesstelephones, such as cellular telephones and Internet Protocol (IP)telephones, can communicate voice and data packets over wirelessnetworks. Many such wireless telephones incorporate additional devicesto provide enhanced functionality for end users. For example, a wirelesstelephone can also include a digital still camera, a digital videocamera, a digital recorder, and an audio file player. Also, suchwireless telephones can process executable instructions, includingsoftware applications, such as a web browser application, that can beused to access the Internet. As such, these wireless telephones caninclude significant computing capabilities. Reducing unneeded powerconsumption in such devices is desirable to prolong battery life andthus enhance a user experience.

IV. SUMMARY

A communication device such as a mobile phone may send a message to anaccess network indicating that a data session has ended. After a timeperiod has passed following sending the message, the communicationdevice may determine whether to re-send the message. For example, amodem of the communication device may determine whether data has beentransferred during the time period via a wireless channel that supportedthe data session. If no data was transferred during the time period, themessage may be re-sent. As another example, an indication of whether themobile device is in an active state or in a low-power state may beprovided to an application associated with the data session and theapplication may determine whether to re-send the message.

In a particular embodiment, a method is disclosed. The method includessending a message from a communication device to a radio networkcontroller. The message indicates that a data session has ended. Thedata session is supported by a wireless channel between thecommunication device and the radio network controller. The method alsoincludes, after a time period following the sending of the message,selectively sending a second message to the radio network controller.The second message indicates that the data session has ended. The secondmessage is selectively sent based at least in part on whether ameasurement indicates that data was communicated via the wirelesschannel during the time period.

In another particular embodiment, an apparatus is disclosed thatincludes a modem configured to generate a message to be sent from acommunication device to a radio network controller. The messageindicates that a data session has ended. The data session is supportedby a wireless channel between the communication device and the radionetwork controller. The modem is further configured, after a time periodfollowing the sending the message, to selectively provide a secondmessage to be sent to the radio network controller. The second messageindicates that the data session has ended. The second message isselectively provided based at least in part on whether a measurementindicates that data was communicated via the wireless channel during thetime period.

In another particular embodiment, the method includes receiving adormancy request from an application executing at a communicationdevice. The method also includes, in response to the dormancy request,sending a message from the communication device to a radio networkcontroller. The message indicating that a data session has ended. Themethod further includes, after expiration of a time period followingsending of the message, providing state information to the application.The state information indicates whether the communication device is in alow-power state.

In another particular embodiment, the apparatus includes a modemconfigured to receive a dormancy request from an application executingat a communication device and to generate a message to be sent from thecommunication device to a radio network controller in response to thedormancy request. The message indicates that a data session has ended.The modem is further configured to provide state information to theapplication after expiration of a time period following sending of themessage. The state information indicates whether the communicationdevice has transitioned to a low-power state.

In another embodiment, the method includes sending a dormancy request toa modem of a communication device. The method also includes receivingstate information from the modem indicating whether the communicationdevice is in an active state or a low-power state. The method furtherincludes, in response to the state information indicating that thecommunication device is in the active state, selectively sending asecond dormancy request to the modem.

In another embodiment, an apparatus is disclosed that includes anapplication processor configured to send a dormancy request to a modemof a communication device and in response to receiving state informationfrom the modem indicating that the communication device has nottransitioned to a low-power state, selectively send a second dormancyrequest to the modem.

One particular advantage provided by at least one of the disclosedembodiments is reduced power consumption at a communication device byselectively re-sending a message to cause a network to transition thecommunication device to a low-power state after a data session hasended. For example, a first message from the communication device may belost by the network. By re-sending the message, the communication devicemay transition to the low-power state faster than a conventional devicethat waits for network usage timers to expire before transitioning to alow-power state.

Other aspects, advantages, and features of the present disclosure willbecome apparent after review of the entire application, including thefollowing sections: Brief Description of the Drawings, DetailedDescription, and the Claims.

V. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a particular illustrative embodiment of acommunication system including a device with data session end logic;

FIG. 2 is a ladder diagram of a first illustrative embodiment of amethod of determining whether to re-send a message indicating that adata session has ended;

FIG. 3 is a flow diagram of a second illustrative embodiment of a methodof determining whether to re-send a message indicating that a datasession has ended;

FIG. 4 is a ladder diagram of a third illustrative embodiment of amethod of determining whether to re-send a message indicating that adata session has ended;

FIG. 5 is a flow diagram of a fourth illustrative embodiment of a methodof determining whether to re-send a message indicating that a datasession has ended;

FIG. 6 is a block diagram of a first illustrative embodiment of acommunication system including a device configured to selectivelyre-send a data session end message; and

FIG. 7 is a block diagram of a second illustrative embodiment of acommunication system including a device configured to selectivelyre-send a data session end message.

VI. DETAILED DESCRIPTION

Referring to FIG. 1, a first embodiment of a communication system isdepicted and designated 100. The system 100 includes user equipment 102in communication with an access network 104, such as a universal mobiletelecommunications system (UMTS) terrestrial radio access network(UTRAN). The access network 104 is coupled to a core network 106. Thecore network 106 is coupled to a packet-switched network, such as theinternet 108, and is coupled to one or more other networks, such as apublic switched telephone network (PSTN) and/or an integrated servicesdigital network (ISDN) 110.

The user equipment 102 includes a module 112 that may identify a user'ssubscription information, such as a universal subscriber identity module(USIM) coupled to a communication device 114. The communication device114 may be a mobile phone such as a smart phone. As other examples, thecommunication device 114 may be a fixed station, a data terminal, oranother type of communication device. The communication device 114includes data session end logic 140. The user equipment 102 isconfigured to implement the data session end logic 140 to enable reducedpower consumption by sending a first request that requests a dormancystate of the communication device 114 and by determining whether tore-request the dormancy state after the first request has been sent tothe access network 104. For example, the data session end logic 140 maymonitor channel activity during a predetermined time period aftersending the first request or may indicate a power state of thecommunication device 114 via power state status logic to generatemessages to an application at the communication device 114 indicatingwhether the communication device 114 is in a low power state or in anactive state. By re-sending the request for a dormancy state, thecommunication device 114 may be able to enter a low-power state even ifan error occurred during transmission of the first request.

The access network 104 includes wireless communication equipment such asradio equipment to enable the communication device 114 to access thecore network 106. The access network 104 includes multiple regions, suchas registration areas, including a representative registration area 120.Each of the regions includes multiple nodes, such as a representativeNode B 122. Each of the nodes may include receiver and transmitterequipment to communicate with user devices and is coupled to a radionetwork controller, such as a representative radio network controller(RNC) 124.

The core network 106 is coupled to the access network 104 viacommunication paths between the RNCs and various components of the corenetwork 106, such as a serving general packet radio service (GPRS)support node (SGSN) 130 and a mobile services switching center(MSC)/visitor location register (VLR) 134. The SGSN 130 is coupled to ahome location register (HLR)/authentication center (AuC) 138. TheHLR/AuC 138 is also coupled to the MSC/VLR 134, to a gateway GPRSsupport node (GGSN) 132, and to a gateway mobile switching center (GMSC)136. The GGSN 132 is coupled to the internes 108 and the GMSC 136 iscoupled to the PSTN/ISDN 110. The core network 106 includes switchingand routing capability for connecting the user equipment 102 to the PSTN110 (for circuit-switched calls) or to a packet data network (forpacket-switched calls), for mobility and subscriber location management,and for authentication services.

In a particular embodiment, the system 100 is a UMTS system andsignaling is performed in accordance with a signaling protocol stackthat is divided into access stratum (AS) and non-access stratum (NAS).

The non-access stratum (NAS) architecture may include connectionmanagement that handles circuit-switched calls and includes sublayers.The NAS may be responsible for call control (e.g., establish, release),supplementary services (e.g., call forwarding, 3-way calling), and shortmessage service (SMS). The NAS may include session management thathandles packet-switched calls. The NAS may include mobility managementthat handles location updating and authentication for circuit switched(CS) calls. The NAS may include GPRS mobility management that handleslocation updating and authentication for packet switched (PS) calls.

The Access Stratum (AS) architecture may include radio resource control(RRC) protocols that are defined between the UE 102 and the RNC 124 tohandle establishment, release, and configuration of radio resources. TheAS may include radio link control (RLC) protocols that are definedbetween the UE 102 and the RNC 124 to provide segmentation, re-assembly,duplicate detection, and other traditional layer-2 functions. The AS mayinclude medium access control (MAC) protocols that are defined betweenthe UE 102 and the RNC 124 to multiplex user plane and control planedata. The AS may include physical layer protocols that are definedbetween the UE 102 and the Node B to transfer data over a radio link.The interface between the UE 102 and the RNC 124 at the physical layermay handle macrodiversity combining and splitting functions.

The NAS may use services provided by the RRC (upper layer of the AS).The initial direct transfer procedure may be used to establish asignaling connection. The initial direct transfer procedure is also usedto carry the initial higher layer (NAS) messages over the radiointerface. The downlink direct transfer procedure may be used in thedownlink direction to carry NAS messages over the radio interface. Theuplink direct transfer procedure may be used in the uplink direction tocarry NAS messages over the radio interface belonging to a signalingconnection.

Fast dormancy for packet data users is a feature introduced in a thirdgeneration partnership project (3GPP) specification, Release 8. Thefeature of fast dormancy offers multiple advantages. For example, fastdormancy may enable a significant reduction in an amount of time that amobile terminal is required to remain in a connected state. Reducingtime in a connected state may result in a substantial improvement tobattery life. For example, an improvement in standby time of over 100%may be attained, depending on network configuration, on a UMTS deviceusing fast dormancy to send the UE 102 to idle in existing networks. Asa second example, by releasing radio resources not being used and movingthe mobile terminal to an idle state, a UTRAN registration area pagingchannel (URA_PCH) state, or a cell paging channel (CELL_PCH) state, thenetwork could also free up extra capacity that can be used for otherusers.

In the case of some applications, although the device may have completedits data transfer and not be expecting further data exchange, the devicemust wait for the network to transition the device from a dedicated datachannel (CELL_DCH) state or fast access channel (CELL_FACH) state toidle or CELL_PCH or URA_PCH states. This delay may arise in systemswithout fast dormancy because the network has no way of determiningwhether the mobile terminal has more data to transfer and thereforekeeps the mobile in data transfer states (e.g. CELL_DCH or CELL_FACH)for a much longer time period than may be necessary. The network maykeep the mobile in the data transfer state for longer than may benecessary to avoid an additional setup delay for subsequent packet datatransfers, in the event that there are more data packets to transfer.Because the UMTS networks cannot anticipate the data transfercharacteristics of particular applications, user devices may be kept indata transfer states for longer than necessary, potentially resulting inexcessive battery drain at the user device.

The UE's application layer may autonomously determine whether anapplication has any more data to exchange. By use of an applicationlayer acknowledgement (for the data transfer) and application specificinactivity timers, the UE 102 may be able to determine reliably when itis appropriate to send an indication to the network that the applicationdoes not have any more data to exchange.

Fast dormancy enables the UE 102 to send this indication in a RRCsignaling connection release indication (SCRI) message by including acause value indicating ending of data transfer session to the UTRAN 104.The SCRI message including the end of data session cause value indicatesthat the UE 102 no longer needs the indicated signaling connection sincedata transfer is complete, and the network can make an informed decisionon how to handle the UE 102. The network may decide to release thesignaling connection, in which case the network may then decide torelease the RRC connection and let the UE 102 go to idle. Alternatively,the network could keep the UE 102 in a CELL_PCH or URA_PCH state inorder to attain similar battery savings while providing a fasterreconfiguration for data transfer in the future. Fast dormancy thusenables the UE 102 to move from an active data transfer state to an idlestate much faster than a conventional process of waiting for the networkto eventually send a low-power state command.

Fast dormancy enabling the UE 102 to transition to the idle state may beenhanced by the data session end logic 140 of the UE 102. For example,the SCRI message may be sent in an un-acknowledged mode and undercertain circumstances may not be received by the network or a reply bythe network may not be received by the UE 102. The UE 102 may determinewhether to re-send the SCRI message to request release of the signalingconnection and transition to a low-power state, as described furtherwith respect to FIGS. 2-7.

FIG. 2 illustrates a first particular embodiment of a method ofdetermining whether to re-send a message from a communication device toa network indicating that a data session has ended. The example of FIG.2 illustrates operation in an embodiment using fast dormancy of a UMTSnetwork that is not responsive to an SCRI from a mobile device.Signaling is illustrated between a user application 202 and a radioresource control (RRC) of user equipment (UE) (UE-RRC) 204. The userapplication 202 and the UE-RRC 204 may be implemented at the UE 102 ofFIG. 1. The UE-RRC 204 communicates with a radio network controller(RNC) 206 and a packet switched domain (PS CN) 208, such as the RNC 124and the internet 108, respectively, of FIG. 1.

1. The user application 202 (for example, an email client of the UE 102of FIG. 1 that synchronizes 210 with a server at the internet 108 ofFIG. 1 once every ten minutes) makes a packet switched (PS) data callthat will cause the UE-RRC 204 to send a RRC connection request message212 that will establish a RRC connection 214.

2. The PS domain is opened by the UE sending an initial direct transfer(IDT) message 216.

3. The network sets up PS radio bearers (RB's) as part of a RB setupmessage 218 and the UE may send a RB setup complete message 220.

4. The user application 202 ends a data session (e.g. an email clientcompletes receiving data from the server) and triggers a dormancyrequest 222 to a modem (e.g. according to a UMTS protocol) indicatingthat the application 202 has completed transferring data.

5. In response to the dormancy request 222, the UE-RRC layer 204 sends aRRC Signaling Connection Release Indication (SCRI) message 224 thatincludes a cause value indicating ending of data transfer session to thenetwork (e.g. UTRAN). The cause value indicates that the UE no longerneeds the signaling connection since data transfer is complete. A timerT323 is started. The UE may be prohibited from sending (or re-sending)the SCRI message 224 with the information element (IE) “SignalingConnection Release Indication Cause” set to “UE Requested PS DataSession End” while the timer T323 is running.

The network may decide to release the signaling connection, in whichcase the network may release the RRC connection and let the UEtransition to the idle state. Alternatively, the network could keep theUE in the CELL_PCH or URA_PCH state to enable battery savings while alsoenabling a faster reconfiguration for data transfer in the future. TheUE may enter a battery saving state (i.e. RRC state IDLE, CELL_PCH, orURA_PCH) in response to an instruction from the network.

However, as illustrated in FIG. 2, the network may not release thesignaling connection. For example, the network may not receive the RRCSignaling Connection Release Indication (SCRI) message 224 due to badradio conditions. According to a 3GPP specification, delivery of theSCRI message 224 is not guaranteed. As another example, the SCRI message224 may be received but the network may not take the UE to a batterysaving state after receiving the RRC Signaling Connection ReleaseIndication (SCRI) message 224. As another example, the network may havesent a message to transition the UE to a battery saving state but themessage may have been lost (e.g. a RRC connection release sent using aun-acknowledgement mode).

In these cases the UE application layer may not be aware of networkactions on power saving states of the UE. Conventional applications mayinitially trigger the dormancy request 222 but may not be able tore-send the dormancy request to indicate that the data session iscomplete.

For example, an email client may trigger periodic synchronization with aserver to determine if any email is to be downloaded (1), and if emailis to be downloaded the email client downloads the emails (2). Afterdetecting no data for a prolonged period (3), the email client maytrigger the dormancy request 222 to the protocol layer (4) to send theSCRI 224 to the network. The application procedure may end its process(5) and may not detect “no data for prolonged period” so the application202 may not trigger further dormancy requests to protocol layers.

6. The UE-RRC 204 may monitor a radio bearer pipe (i.e. the logical pipethat carries data to the user application 202) for any datatransactions. When the user application 202 triggers the dormancyrequest 222 to the UE protocol, the UE-RRC 204 will send the SCRImessage 224 by setting the IE “Signaling Connection Release IndicationCause” to “UE Requested PS Data Session End” to the network. The UE willremember that the application 202 requested dormancy and that theapplication 202 does not have any data to send.

In one embodiment, the UE starts monitoring the radio bearer pipe thatcarries user application data to determine if any uplink data is sent orany downlink data is received by polling on a counter “Count_C.” Thecounter provides a number that is incremented in case any data is sentor received. In another embodiment, the UE starts monitoring the radiobearer pipe that carries user application data to determine if anyuplink data is sent or any downlink data is received by polling on a RLCsequence number that is incremented in case any data is sent orreceived.

Upon expiry 226 of the timer T323, if the network has not transitionedthe UE to a battery saving state (i.e. the UE does not have batterysavings from transitioning to a low-power state), the UE checks whetherthere is any activity on the user radio link control (RLC) pipe. Upondetermining that there was no activity on the RLC pipe at the UE duringthe time period between when the T323 timer is started and the expiry226 of the T323 time, the UE sends a SCRI message 230 to the network andstarts monitoring the user RLC pipe. UE may continue repeating the SCRIsend/run T323/check for inactivity process for up to N number of cycles(N is a positive integer). The UE may stop the process of polling theradio bearer pipe if the network transitions the UE to a battery savingstate.

As a result, because the UE-RRC 204 monitors the radio bearer (e.g.based on Count-C or RLC sequence number), determining whether datatransmission has ceased after sending the SCRI message 224 anddetermining whether to send the SCRI 230 may occur at the UE-RRC 204independent of the application 202. The UE provides a centralizedpolling mechanism that will selectively send the SCRI 230 even if theapplication 202 shuts down after sending the dormancy request 222. TheUE protocol may also provide efficient access to RRC state informationto determine whether the UE is in a battery saving state or not.

FIG. 3 depicts a second illustrative embodiment of a method ofselectively resending a dormancy request at a mobile device. The method300 includes sending a message indicating that a data session has ended,at 302. For example, the message may be sent from a communication deviceto a radio network controller, such as a SCRI message sent from thecommunication device 114 of FIG. 1 to the representative radio networkcontroller 124 of the UTRAN 104 of FIG. 1. The data session may besupported by a wireless channel between the controller and an accessnetwork, such as the radio bearer (RB) established between the UE-RCC204 and the RNC 206 via messages 218-220 of FIG. 2.

A determination is made whether a time period has expired, at 304. Forexample, the time period may be a predetermined time period. Toillustrate, the predetermined time period may correspond to a timeperiod from starting a T323 timer and expiry of the T323 timer of a UMTSsystem. When the time period has not ended (e.g. the timer has notexpired), processing returns to 304.

When the time period has ended (e.g. the timer has expired), processingadvances to determinate whether the communication device is in a lowpower state, at 306. If the communication device is determined to be inthe low-power state, at 306, the method ends, at 308. However, if thecommunication device is determined to not be in the low-power state at306, processing advances to 310, where a determination is made whether ameasurement indicates that data was communicated via the wirelesschannel during the time period.

When the measurement indicates that data was communicated during thetime period, the method ends at 308. When the measurement indicates thedata was not communicated by the wireless channel during the timeperiod, a determination may be made whether a count of a number ofmessages sent exceeds a threshold, at 312. When the count of a number ofmessages sent does not exceed the threshold, at 312, processing returnsto 302, where a next message is sent indicating that the data sessionhas ended. For example, the next message may be a resending of an SCRImessage. However, when the count of sent messages exceeds the threshold,at 312, the method ends at 308.

The method 300 includes sending a message from a communication device toa radio network controller. The communication device may be configurableto transition between an active state and a low-power state and thecommunication device is in the active state when the message is sent.The low-power state may include one or more of an idle state, a cellpaging channel monitoring state (CELL_PCH), a registration area pagingchannel monitoring state (URA_PCH), or any combination thereof.

The message indicates that a data session between the communicationdevice and the radio network controller has ended and may include asignaling connection release indication (SCRI) that includes a signalingconnection release indication cause information element (IE) thatindicates a user equipment (UE) requested packet switched (PS) datasession end. The data session is supported by a wireless channel betweenthe communication device and the radio network controller.

The wireless channel may be monitored during a time period that beginsupon sending the message. An end of the time period may be determinedbased on expiration of a message inhibit timer (e.g. T323) that is setin response to sending the message. A value of a parameter may bemodified in response to data being communicated via the wireless channelduring the time period. For example, the parameter may be a count(Count-C) that is incremented in accordance with a universal mobiletelecommunication service (UMTS) specification in response to detectinga protocol data unit (PDU) data communication via the wireless channel.As another example, the parameter may be a radio link control (RLC)sequence number that is incremented in accordance with a universalmobile telecommunication service (UMTS) specification and that may beprovided as a sequence number in a PDU header. A first value of theparameter at a beginning of the time period may be compared to a secondvalue of the parameter at the end of the time period to determinewhether data was communicated over the wireless channel during the timeperiod.

After expiration of the time period after sending the message, themethod includes selectively sending a second message (e.g. a secondSCRI, or resending the same message as the first message) to the radionetwork controller, the second message indicating that the data sessionhas ended. The second message is selectively sent based on whether ameasurement indicates that data was communicated via the wirelesschannel during the time period.

The method may include selectively sending a third or subsequent messagebased on a count of messages that have been sent after the data sessionhas ended when the count of messages does not exceed a predeterminedthreshold. The third message indicates that the data session has ended.For example, when the count of messages does not exceed the threshold,at 312, another message may be sent indicating that the data session hasended, at 302.

As a result, if the first message is lost or if a network reply to thefirst message is not received, the communication device may re-send themessage to the network. If the second or subsequent message is receivedand acted upon by the network, the communication device may be able totransition to a low-power state without having to wait for conventionaltime periods of non-activity before transitioning to the low-powerstate.

FIG. 4 illustrates a third embodiment of a method of determining whetherto re-send a message indicating that a data session has ended. Theexample of FIG. 4 illustrates operation in an embodiment using fastdormancy of a UMTS network that is not responsive to an SCRI from amobile device. Signaling is illustrated between a user application 402and a radio resource control (RRC) of user equipment (UE) (UE-RRC) 404with a radio network controller (RNC) 406 and a packet switched domain(PS CN) 408. For example, FIG. 4 may correspond to communication of theUE 102 to the internet 108 via the access network 104 of FIG. 1.

1. The user application 402 (for example, an email client thatsynchronizes 410 with a server once every ten minutes) makes a packetswitched (PS) data call that causes the UE-RRC 404 to send a RRCconnection request message 412 to establish a RRC connection 414.

2. The PS domain is opened by the UE sending an initial direct transfer(IDT) message 416.

3. The network sets up PS radio bearers (RB's) as part of a RB setupmessage 418 and the UE may send a RB setup complete message 420.

4. The user application 402 ends a data session (e.g. an email clientcompletes receiving data from the server) and triggers a dormancyrequest 422 to a modem (e.g. according to a UMTS protocol) indicatingthat the application 402 has completed transferring data.

5. In response to the dormancy request 422, the UE-RRC layer 404 sends aRRC Signaling Connection Release Indication (SCRI) message 424 thatincludes a cause value indicating ending of data transfer session to thenetwork (e.g. UTRAN) that the UE no longer needs the signalingconnection since data transfer is complete. The UE initiates a timerT323 start 426. The UE may be prohibited from sending (or resending) theSCRI message 424 with the information element (IE) “Signaling ConnectionRelease Indication Cause” set to “UE Requested PS Data Session End”while the timer T323 is running.

6. The network may release the signaling connection, in which case thenetwork may release the RRC connection or reconfigure the UE to abattery saving state 428. The network may send a message 430 including aRRC connection release instruction or a RB reconfiguration instructionfor PS RB's. The UE may send a message 432 indicating a RRC connectionrelease and/or a RB reconfiguration is complete. The UE may enter abattery savings state 434.

7. At expiry of timer T323 (i.e. at the end of the time period startingupon the SCRI 424 being sent and ending upon the timer T323 expiring),the UE protocol will indicate a current RRC state 436 to the userapplication 402. For example, the RRC state 436 may be an active state(e.g. CELL_DCH or CELL_FACH) or a low-power state (e.g. idle, CELL_PCH,or URA_PCH). The user application 402 may receive the RCC stateinformation and determine whether to send another dormancy request tothe UE protocol (e.g., re-send the dormancy request 422).

As a result, a determination of whether to re-send the SCRI message 424may be made by the application 402 that triggered the dormancy requestrather than by the UE-RRC 404 monitoring the radio bearer (as analternative to the embodiments of FIGS. 2-3). The embodiment illustratedin FIG. 4 enables each user application 402 to implement customizedlogic to determine how to respond to a failure of the network totransition the UE to a low-power state after the user application 402sends the dormancy request 422.

FIG. 5 illustrates a fourth embodiment of a method of selectivelyresending a dormancy request. The method 500 includes determiningwhether a dormancy request is received from an application executing ata communication device, at 502. For example, the application may be theuser application 402 of FIG. 4. When it is determined that a dormancyrequest is received from an application executing at the communicationdevice, a message is sent indicating that a data session has ended, at504. The message may be sent from the communication device to a radionetwork controller, such as the SCRI message 424 sent to the RNC 406 ofFIG. 4. The communication device may be configurable to transitionbetween an active state and a low-power state, and the communicationdevice may be in the active state when the message is sent.

A determination is made whether a time period following the sending ofthe message has expired, at 506. For example, the time period may be thetime period described with respect to FIG. 4. After the time period hasended, state information is provided to the application, at 508. Thestate information may indicate whether the communication device is in alow-power state. To illustrate, the state information may include anindication of a current radio resource control (RRC) state, such as anactive state (e.g. CELL_DCH or CELL_FACH) or a low-power state (e.g.idle, CELL_PCH, or URA_PCH).

After sending the state information to the application, processingreturns to 502, where it is determined whether a second dormancy requesthas been received from the application. In response to receiving asecond dormancy request from the application, a second message may besent from the communication device to the radio network controllerindicating that the data session has ended.

As a result, if the first message is lost or if a network reply to thefirst message is not received, the application may determine to re-sendthe message to the network. If the second or subsequent message isreceived and acted upon by the network, the communication device may beable to transition to a low-power state without having to wait forconventional time periods of non-activity before transitioning to thelow-power state.

FIG. 6 illustrates a particular embodiment of a system 600 including acommunication device 602, such as a smart phone. The communicationdevice 602 includes a display device 604 and a user input device 606operatively coupled to an application processor 608. The applicationprocessor 608 is coupled to a memory 610 and to a modem 616. The modem616 is coupled to a transceiver 618 that is coupled to an antenna 620.The communication device 602 is configured to send and receive data 662via a wireless channel 660. For example, the wireless channel 660 may bea radio bearer in accordance with a UMTS specification. In a particularembodiment, the communication device 602 may correspond to the UE 102 ofFIG. 1 and may be configured to selectively re-send a message indicatingan end of a data session according to the method of FIG. 2 or FIG. 3.

The modem 616 includes a processor 622 running a protocol stack 632 thatenables communication via the wireless channel 660. The modem 616 may beconfigured to implement the data session end logic 140 of FIG. 1. Forexample, the modem 616 may be configured to operate in accordance withthe UE-RRC 204 of FIG. 2. As another example, the modem 616 may beconfigured to operate in accordance with the method 300 of FIG. 3.

The protocol stack 632 may include a message generator module 634 and achannel activity detector 636. The modem 616 also includes a memory 624that stores modem code 638. For example, the modem code 638 may includeprocessor executable instructions that are executable by the processor622 to implement part or all of the protocol stack 632. For example, themodem code 638 may include instructions that are executable by theprocessor 622 to generate one or more messages by the message generator634. As another example, the modem code 638 may be executable by theprocessor 622 to determine data is transmitted or received via thechannel 660 via the channel activity detector 636. The channel activitydetector 636 may be configured to detect data transfer during a timeperiod following sending a message indicating the end of a data session.

The modem 616 includes a one or more registers, such as a count register626. The count register 626 may include a first value Count-C 640, asecond value indicating a sequence number 642, or a combination thereof.For example, the Count-C value 640, the sequence number 642, or both maybe incremented in response to detecting a data transmission being sentvia the wireless channel 660 or received from the communication channel660. The Count-C value 640 and the sequence number 642 may be maintainedand incremented according to a UMTS protocol and may be polled todetermine whether data has been transferred during a time periodfollowing sending a message indicating the end of a data session.

The modem 616 includes one or more call timers 628. For example, themodem 616 includes a T323 timer 644. The modem 616 also includes one ormore state registers 630. For example, the state register 630 may storeone or more values that indicate whether the modem is in a low powerstate 646 or an active state 648. To illustrate, the low power state mayinclude one or more of an idle state, a cell paging channel monitoringstate (CELL_PCH), a registration area paging channel monitoring state(URA_PCH), or any combination thereof.

The application processor 608 may be configured to execute one or moreapplications, such as a representative application 614. To illustrate,the application 614 may include a web browser, an audio or videoplayback device application, one or more user applications or databasesynchronization software. The application processor 608 may implementthe application 614 by execution of application code 612 from the memory610. For example, the application code 612 may include processorexecutable instructions that are executable by the application processor608 to implement the application 614.

During operation, the application 614 may be configured to communicatedata 650 to the modem 616 during a data session with a remote device,such as a remote server, and in response the modem 616 may transmit oneor more packets of data 662 via the wireless channel 660. To illustrate,the application 614 may implement a data session with a remote dataserver to send and receive one or more bursts of data packets via thedata channel 660. In response to the application 614 determining thatthe data session has ended, the application 614 may generate a dormancyrequest 652 that is sent to the modem 616. The modem 616 may receive thedormancy request 652 and in response the message generator 634 maygenerate a message to be transmitted to an access network, such as tothe RNC 124 of FIG. 1, indicating that the data session has ended and/orrequesting the modem to be transferred to the low-power state 646. Forexample, the message generator 634 may generate a SCRI message.

After sending the message, the channel activity detector 636 may pollthe count register 626 to determine a value of Count-C 640, a value ofthe sequence number 642, or a combination thereof. In addition, the T323timer 644 may be started when the message is sent. Upon expiry of theT323 timer 644, the channel activity detector 636 may determine byaccessing the state register 630 whether the communication device 602 isin the low power state 646. In addition, the channel activity detector636 may poll the count register 626 to determine another value ofCount-C 640 or the sequence number 642. Upon determining that thecommunication device 602 is in the low power state 646, the protocolstack 632 may be configured to recognize that the wireless channel 660has been closed.

However, upon determining that the communication device 602 is not inthe low power state 646 and instead is in an active state 648, themessage generator 634 may be configured to resend the message (e.g. theSCRI message), or to send a second message (e.g. a second SCRI message)indicating that the data session has ended. To illustrate, the channelactivity detector 636 may poll the count register 626 upon completion ofthe T323 timer 644. Upon detecting that a value of the Count-C parameter640 at the expiration of the T323 timer 644 differs from an initialvalue of the Count-C parameter 640 (when the message is sent), thechannel activity detector 636 may determine that the wireless channel660 is still in use, and rules or logic associated with the protocolstack 632 may determine that a second message indicating that the datasession has ended should not be sent. As another example, the channelactivity detector 636 may perform a similar comparison of values of thesequence number 642 to determine whether data is communicated via thewireless channel 660 during a time period of the T323 timer 644. Inresponse to the channel activity detector 636 determining that no datahas been communicated via the wireless channel 660 during a time periodassociated with the T323 timer 644, the message generator 634 may resendthe message to the access network indicating the data session has ended.

Therefore, if the message was not delivered to the network or if anetwork reply to the first message is not received, the communicationdevice 602 can re-send the message to the network. The communicationdevice 602 may be able to transition to a low-power state without havingto wait for conventional time periods of non-activity beforetransitioning to the low-power state.

Referring to FIG. 7, a system 700 is depicted that includes acommunication device 702 with access to a wireless channel 760. Thecommunication device 702 includes a display device 704 and a user inputdevice 706 operatively coupled to an application processor 708. Theapplication processor 708 is configured to implement an application 714by executing application code 712 at a memory 710. For example, thememory 710 may be a non-transient tangible storage medium storingprocessor executable instructions. The application processor 708 iscoupled to a modem 716. The modem 716 enables communication via thewireless channel 760 using a transceiver 718 and an antenna 720.

The modem 716 includes a processor 722, a memory 724, one or more calltimers 728, and a state register 730. The modem 716 may be configured toimplement the data session end logic 140 of FIG. 1. For example, themodem 716 may be configured to operate in accordance with the UE-RRC 404of FIG. 4. As another example, the modem 716 may be configured tooperate in accordance with the method 500 of FIG. 5.

The processor 722 may be configured to implement a protocol stack 732.For example, the processor 722 may be configured to execute processorexecutable instructions such as modem code 738 stored at the memory 724.The modem code 738 may include processor executable instructions thatare executable by the processor 722 to implement the protocol stack 732.The protocol stack 732 may include a message generator 734. The messagegenerator 734 may be configured to generate one or more messages toindicate to a radio network controller of an access network, such as aSCRI message sent to the radio network controller 124 of FIG. 1, an endof a data session that is supported by the wireless channel 760.

The one or more call timers 728 may include a T323 timer 744 that isconfigured to indicate expiration of a predetermined duration followingtransmission of a SCRI message, such as a first SCRI message 768 or asecond SCRI message 770. The state register 730 may be configured torecord data indicating whether the communication device 702 is in a lowpower state 746 or an active state 748.

The application processor 708 may implement an application 714 thatincludes a dormancy request module 764. The dormancy request module 764may be configured to send a first dormancy request 774 to the modem 716in response to determining that a data session has ended. For example,the data session may be used by the application 714 to send and receivedata 772 to a remote source via the wireless channel 760. Upondetermination that the data session has ended, the application 714 maysend the first dormancy request 774 to the protocol stack 732.

The protocol stack 732 may be configured to generate the first SCRImessage 768 using the message generator 734 and to send the first SCRImessage 768 via the wireless channel 760. The first SCRI 768 indicatesthat the data session has ended. Upon sending the first SCRI 768, theT323 timer 744 may be initiated. Upon expiration of the T323 timer 744,the protocol stack 732 may be configured to send state information 776to the application 714 indicating a state of the communication device702. For example, the modem 716 may provide the state information 776 byreading content of the state register 730 and by providing an indicationof a current radio resource control (RRC) state to the application 714.

The application 714 may receive the state information 776 from the modem716 indicating whether the communication device 702 is in the activestate 748 or the low power state 746. When the state information 776indicates that the communication device 702 is in the low-power state746, the network has responded to the first SCRI 768 and the wirelesschannel 760 has been released, as triggered by the first dormancyrequest 774. In response to the state information 776 indicating thatthe communication device 702 is in the active state 748, the dormancyrequest module 764 may selectively send a second dormancy request 778 tothe modem 716. For example, the second dormancy request 778 may be sentin response to a determination by the application 714 that no data ispending to be transferred via the modem 716.

Upon receiving the second dormancy request 778 at the modem 716, themessage generator 734 may send the second SCRI message 770, againrequesting to close the communication channel 760 and/or to betransitioned into the low power state 746.

Therefore, if the first SCRI 768 is lost or if a network reply to thefirst SCRI 768 is not received, the application 714 may determine tosend the second SCRI 770 to the network. If the second or subsequentSCRI is received and acted upon by the network, the communication device702 may be able to transition to the low-power state 746 without havingto wait for conventional time periods of non-activity beforetransitioning to the low-power state 746.

Those of skill would further appreciate that the various illustrativelogical blocks, configurations, modules, circuits, and algorithm stepsdescribed in connection with the embodiments disclosed herein may beimplemented as electronic hardware, computer software executed by aprocessor, or combinations of both. Various illustrative components,blocks, configurations, modules, circuits, and steps have been describedabove generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or processor executableinstructions depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

The steps of a method or algorithm described in connection with theembodiments disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), programmable read-only memory (PROM),erasable programmable read-only memory (EPROM), electrically erasableprogrammable read-only memory (EEPROM), registers, hard disk, aremovable disk, a compact disc read-only memory (CD-ROM), or any otherform of non-transient storage medium known in the art. An exemplarystorage medium is coupled to the processor such that the processor canread information from, and write information to, the storage medium. Inthe alternative, the storage medium may be integral to the processor.The processor and the storage medium may reside in anapplication-specific integrated circuit (ASIC). The ASIC may reside in acomputing device or a user terminal (e.g. a mobile phone). In thealternative, the processor and the storage medium may reside as discretecomponents in a computing device or user terminal.

The previous description of the disclosed embodiments is provided toenable a person skilled in the art to make or use the disclosedembodiments. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the principles defined hereinmay be applied to other embodiments without departing from the scope ofthe disclosure. Thus, the present disclosure is not intended to belimited to the embodiments disclosed herein but is to be accorded thewidest scope possible consistent with the principles and novel featuresas defined by the following claims.

1. A method comprising: sending a message from a communication device to a radio network controller, the message indicating that a data session has ended, wherein the data session is supported by a wireless channel between the communication device and the radio network controller; and after a time period following the sending of the message, selectively sending a second message to the radio network controller, the second message indicating that the data session has ended, wherein the second message is selectively sent based at least in part on whether a measurement indicates that data was communicated via the wireless channel during the time period.
 2. The method of claim 1, wherein the message includes a signaling connection release indication (SCRI).
 3. The method of claim 2, wherein the SCRI includes a signaling connection release indication cause information element (IE) that indicates a user equipment (UE) requested packet switched (PS) data session end.
 4. The method of claim 1, wherein the wireless channel is monitored during the time period and wherein a value of a parameter is modified in response to data being communicated via the wireless channel during the time period and further comprising comparing a first value of the parameter at a beginning of the time period to a second value of the parameter at an end of the time period.
 5. The method of claim 4, wherein the parameter is a count (Count-C) that is incremented in accordance with a universal mobile telecommunication service (UMTS) specification in response to data being communicated via the wireless channel.
 6. The method of claim 4, wherein the parameter is a radio link control (RLC) sequence number that is incremented in accordance with a universal mobile telecommunication service (UMTS) specification.
 7. The method of claim 1, wherein the second message is a same message as the message.
 8. The method of claim 1, wherein a third message is selectively sent based on a count of messages sent after the data session has ended not exceeding a predetermined threshold, the third message indicating that the data session has ended.
 9. The method of claim 1, wherein an end of the time period is determined based on expiration of a message inhibit timer that is set in response to sending the message.
 10. The method of claim 1, wherein the communication device is configurable to transition between an active state and a low-power state, and wherein the communication device is in the active state when the message is sent.
 11. The method of claim 10, wherein the low-power state includes one or more of an idle state, a cell paging channel monitoring state (CELL_PCH), a registration area paging channel monitoring state (URA_PCH), or any combination thereof.
 12. An apparatus comprising: a modem configured to generate a message to be sent from a communication device to a radio network controller, the message indicating that a data session has ended, wherein the data session is supported by a wireless channel between the communication device and the radio network controller, wherein the modem is further configured, after a time period following sending of the message, to selectively provide a second message to be sent to the radio network controller, the second message indicating that the data session has ended, wherein the second message is selectively provided based at least in part on whether a measurement indicates that data was communicated via the wireless channel during the time period.
 13. The apparatus of claim 12, wherein the modem is configured to monitor the wireless channel during the time period and to modify a value of a parameter in response to data being communicated via the wireless channel during the time period, and wherein the modem is further configured to compare a first value of the parameter at a beginning of the time period to a second value of the parameter at an end of the time period.
 14. The apparatus of claim 13, wherein the parameter is a count (Count-C) that is incremented in response to data being communicated via the wireless channel.
 15. The apparatus of claim 13, wherein the parameter is a radio link control (RLC) sequence number.
 16. A computer-readable medium storing processor-executable instructions that are executable to cause the processor to: generate a message to be sent from a communication device to a radio network controller, the message indicating that a data session has ended, wherein the data session is supported by a wireless channel between the communication device and the radio network controller; and after a time period following the sending of the message, selectively provide a second message to be sent to the radio network controller, the second message indicating that the data session has ended, wherein the second message is selectively provided based at least in part on whether a measurement indicates that data was communicated via the wireless channel during the time period.
 17. The computer-readable medium of claim 16, wherein the wireless channel is monitored during the time period, wherein a value of a parameter is modified in response to data being communicated via the wireless channel during the time period, and wherein the processor-executable instructions further include instructions to cause the processor to compare a first value of the parameter at a beginning of the time period to a second value of the parameter at an end of the time period.
 18. The computer-readable medium of claim 17, wherein the parameter is a count (Count-C) that is incremented in response to data being communicated via the wireless channel.
 19. The computer-readable medium of claim 17, wherein the parameter is a radio link control (RLC) sequence number.
 20. An apparatus comprising: means for generating a first message to be sent from a communication device to a radio network controller, the message indicating that a data session has ended, wherein the data session is supported by a wireless channel between the communication device and the radio network controller, and for selectively providing a second message to be sent to the radio network controller after a time period following sending of the first message, the second message indicating that the data session has ended; and means for determining whether data is communicated via the wireless channel during the time period, wherein the second message is selectively provided based at least in part on whether the data was communicated via the wireless channel during the time period.
 21. The apparatus of claim 20, wherein the wireless channel is monitored during the time period and a value of a parameter is modified in response to data being communicated via the wireless channel during the time period, and wherein the means for determining is configured to compare a first value of the parameter at a beginning of the time period to a second value of the parameter at an end of the time period.
 22. The apparatus of claim 21, wherein the parameter is a count (Count-C) that is incremented in response to data being communicated via the wireless channel.
 23. The apparatus of claim 21, wherein the parameter is a radio link control (RLC) sequence number.
 24. A method comprising: receiving a dormancy request from an application executing at a communication device; in response to the dormancy request, sending a message from the communication device to a radio network controller, the message indicating that a data session has ended; and after expiration of a time period following sending of the message, providing state information to the application, the state information indicating whether the communication device is in a low-power state.
 25. The method of claim 24, further comprising in response to receiving a second dormancy request from the application, sending a second message from the communication device to the radio network controller, the second message indicating that the data session has ended.
 26. The method of claim 24, wherein the state information includes an indication of a radio resource control (RRC) state.
 27. The method of claim 24, wherein the communication device is configurable to transition between an active state and the low-power state, and wherein the communication device is in the active state when the message is sent.
 28. A computer-readable medium storing processor-executable instructions that are executable to cause the processor to: receive a dormancy request from an application executing at a communication device; in response to the dormancy request, generate a message to be sent from the communication device to a radio network controller, the message indicating that a data session has ended; and after expiration of a time period following sending of the message, provide state information to the application, the state information indicating whether the communication device has transitioned to a low-power state.
 29. The computer-readable medium of claim 28, wherein the processor-executable instructions further include instructions to cause the processor to, in response to receiving a second dormancy request from the application, provide a second message to be sent from the communication device to the radio network controller indicating that the data session has ended.
 30. The computer-readable medium of claim 28, wherein the state information includes an indication of a radio resource control (RRC) state.
 31. An apparatus comprising: a modem configured to receive a dormancy request from an application executing at a communication device and to generate a message to be sent from the communication device to a radio network controller in response to the dormancy request, the message indicating that a data session has ended, wherein the modem is further configured to provide state information to the application after expiration of a time period following sending of the message, the state information indicating whether the communication device has transitioned to a low-power state.
 32. The apparatus of claim 31, wherein the modem is further configured to, in response to receiving a second dormancy request from the application, provide a second message to be sent from the communication device to the radio network controller, the second message indicating that the data session has ended.
 33. The apparatus of claim 31, wherein the state information includes an indication of a current radio resource control (RRC) state.
 34. An apparatus comprising: means for generating a message to be sent from a communication device to a radio network controller in response to receiving a dormancy request from an application executing at the communication device, the message indicating that a data session has ended; and means for receiving the dormancy request from the application and for providing state information to the application after a time period following sending of the message, the state information indicating whether the communication device has transitioned to a low-power state.
 35. The apparatus of claim 34, wherein the means for generating further includes means for providing a second message to be sent from the communication device to the radio network controller indicating that the data session has ended in response to receiving a second dormancy request from the application.
 36. The apparatus of claim 34, wherein the state information includes an indication of a current radio resource control (RRC) state.
 37. A method comprising: sending a dormancy request to a modem of a communication device; receiving state information from the modem indicating whether the communication device is in an active state or a low-power state; and in response to the state information indicating that the communication device is in the active state, selectively sending a second dormancy request to the modem.
 38. The method of claim 37, wherein the modem operates according to a universal mobile telecommunications system (UMTS) protocol, wherein the dormancy request corresponds to a fast dormancy request, and wherein the state information includes radio resource control (RRC) information.
 39. The method of claim 37, wherein the second dormancy request is sent in response to a determination that no data is pending to be transferred via the modem.
 40. A computer-readable medium storing processor-executable instructions that are executable to cause the processor to: send a dormancy request to a modem of a communication device; receive state information from the modem indicating whether the communication device is in an active state or a low-power state; and in response to the state information indicating that the communication device is in the active state, selectively send a second dormancy request to the modem.
 41. An apparatus comprising: an application processor configured to send a dormancy request to a modem of a communication device and in response to receiving state information from the modem indicating that the communication device has not transitioned to a low-power state, selectively send a second dormancy request to the modem.
 42. An apparatus comprising: means for sending a dormancy request to a modem of a communication device and for receiving state information from the modem; and means for determining whether to send a second dormancy request to the modem when the state information indicates that the communication device has not transitioned to a low-power state. 